I should clarify, at present users are not able to upload attachments and typically link to off-site images. I can't really change that on a large scale, because my users will overwhelm my available space pretty quickly.
Currently, I'm using vB4 to manage a comicbook artwork forum. I use this hack ...
http://www.vbulletin.org/forum/showthread.php?t=237650&page=10
(SevenSkins ImageResizer) to ensure users don't post massive pictures inline and cause the forum to side-scroll perpetually, etc.
Is there any...